酵母生物合成S-腺苷-L-蛋氨酸的动力学研究

Study on the Kinetics of Biosynthesis of S-adenosyl-L-methionine by Yeast Cells

研究了酿酒酵母在葡萄糖和L-蛋氨酸存在时生物合成S-腺苷-L-蛋氨酸(SAM)的规律。在高溶氧(DO>40%)条件下,SAM产率及L-蛋氨酸转化率分别达到了82.2 mgg-1和37.4%。将代谢溢流模型推广应用到包括酵母生长和加前体生物转化过程的动力学研究,结果表明,该模型能较好地描述实验数据。

Under different dissolved oxygen level, the biosynthesis of S-adenosyl-L-methionine (SAM) was evaluated in a 15L fermentor with the pre-cultured S. cerevisiae in presence of glucose and L-methionine. At high dissolved oxygen level (DO>40%), the productivity of SAM and the conversion ratio of L-methionine reached as high as 82.2 mgg-1 dry cell weight and 37.4%, respectively. A modified metabolic overflow model was applied to the system to describe the substrate uptake, cell growth, product accumulation and the cell respiration capacitiy. The model simulations were in good agreement with the experimental data and the calculated values of respiration capacitiy indicated that the respiration capacitiy was limited by oxygen supply during the biotransformation phase.